Error Codes of STS Prepayment Meters

STS (Standard Transfer Specification) prepayment meters take digital medium as information exchange media. Users load in pre-purchased credit and then the meters take credit as their billing to realize the functions of active energy measuring and prepayment control and realize remote communication and remote control via module.
Local power companies or utilities use prepayment meters to avoid debts by charging power bills in advance. Additionally, prepayment smart meters with automatic reading function reduces cost of manual collecting meter data.
For end-customers, they can check their meter load in real time to use power reasonably. They can also recharge meters in any place and any time, instead of going to local power company to pay for.

CLOU STS Prepayment Meters

We have many STS prepayment meters, such as CL730S22 and CL710K22. You can also find more information about prepayment meters here.

Single Phase Meter CL710K22
Single Phase Meter CL710K22
Three Phase Meter CL730S22
Three Phase Meter CL730S22

Differences between TOKEN and Meter Numbers

TOKEN numbers and meter numbers are two totally different things.
According to the STS standard, a TOKEN has only complete 20 digits.
While CLOU STS meters have 11 digits. Other CLOU meters also have 12 digits.
The length of meter numbers is customized.
When you input a Token by which the prepayment meter can not work, the meter will show error codes. Specific reasons are cited one by one as below. If your meter equips an UIU (User Interface Unit), error codes also shows on its LCD.

Error Codes Shown on CLOU Prepayment Meter

CLOU regulates prepayment meter error codes in a certain statement according to the IEC62055-41 chapter 7.1. Almost all CLOU prepayment meters have the same error codes.
Here takes error codes shown on the CL730S22 three-phase meter as an example.

Meter Display Information

  • OPEN Any meter cover was opened
  • DISTU Magnetic disturbance detected
  • OVER PO Power exceeds the limit
  • VOL-OVER Voltage is over allowed threshold
  • CUR-OVER Current is over allowed threshold
  • CUR-UNB Current unbanlance occured
  • N-DST Neutral line is disturbed
  • CT-BYPAS Meter is bypassed
  • CT-OPEN Meter current circuit is open
  • VOL-UNB Voltage is unbalanced
  • HIGH-TMP Temperature too high
  • LOW-PF Power factor too low

UIU Display Information

  • ACCEPT TOKEN accepted
  • REJECT TOKEN rejected. The 20-digit TOKEN input is not generated from the designated platform.
  • OLD TOKEN expired
  • USED TOKEN used
  • FULL Overflow error. The credit register in the payment meter would overflow if the token were to be accepted; the token is not accepted.
  • OK Operation accepted
  • Err_01 Error in manufacturer code. The Manufacturer Code value in the Class 1 token does not match the Manufacturer Code value for the Decoder.
  • Err_02 Key expired error. The TID (Token Identifier) value as record in the token is larger than the KEN (Key Expiry Number)stored in the payment meter memory.
    Solution: First, please check your meter KEN value if it has expansion space or not; If the number is already maximum, shift the TID and change the Base Date in the energy selling system into “2014” option.
  • Err_03 DDTK (Decoder Default Transfer Key) error. The Decoder has a DDTK value in the DKR (Decoder Key Register): a Transfer Credit token may not be processed by the Meter Application Process in accordance with the values given in credit.
  • Err_04 Overflow error. The credit register in the payment meter would overflow if the token were to be accepted; the token is not accepted. (Some meter types are showing Err_04 instead of FULL).
  • Err_05 Key type error. The key may not be changed to this type in accordance with the key change rules.
  • Err_06 TOKEN format error. One or more data elements in the token does not comply with the required format for that element. That’s say, to aviod this error, 20 digits of the TOKEN are correct and complete, and the TOKEN must be valid and unused. For example, the error shows when one only inputs 19 digits.
  • Err_07 TOKEN range error. One or more data elements in the token have a value that is outside the defined range of values defined in the application for that elements.
  • Err_08 TOKEN Function error. The particular function to execute the token is not available.
  • NULL Reserved

Troubleshooting to Pairing A UIU with A Meter

If something wrong happens while paring a UIU (User Interface Unit) with an energy meter, the following steps can be taken to initiate the UIU for troubleshooting.

  • Step1: Input “1593570” + “999” + “Enter” to initialize the UIU.
  • Step2: Input “1593570” + “11-digit meter number” + “Enter” to pair the meter with UIU.
  • Step3: Input “999” + “enter” to check the paired meter, and “12-digit address” will be displayed on the UIU.


So far, we have received a great number of comments about meter error codes and TOKEN. This article aims to at least provide a fundamental explanation to error codes.
For visitors who are finding information about them, wish this article can help you.
If you have more questions about error codes, just leave a comment below to discuss it.
Thank you for your reading and best wishes.

Editor's note: This article was originally published in November 2021 and has been updated for comprehensiveness.

86 Replies to “Error Codes of STS Prepayment Meters”
  1. I loaded credit on my STS MMX prepaid meter, the token was accepted but the credit didn’t take effect like no light in my apartment. What can I do?

    1. The MMX meter is from a different manufacturer, so we can only cover the general actions. If the meter was running out of credit before you have topped-up, you most likely need to close the internal relay. (For CLOU meters, it’s short code 00 and enter.) Look at your short reference or ask your power company.
      Another possibility is, that the meter is in tamper mode. Then you need a clear tamper code, also from your power company.

    1. The overdraft- or emergency credit function is preset by the utility and can’t be changed with a code.

    1. Thanks for your comment. Err-04 indicates, credit is overflow or still negative. Please check your credit value first.

  2. Perhaps my question wasn’t clear enough, permit me to rephrase; my Cl710k11 uiu keeps reading when all gadgets are turned off (as well as when the rewireable fuse is disconnected) sometimes fast sometimes slow or normal and when the unit on my meter gets exhausted, and there is power supply in my neighbourhood, it keeps reading into negative figures but if there is a general power outage, it stops reading until the power supply is restored (meaning the reading remains the same until power supply is restored). This happens to my apartment alone, all other apartments have their Cl710k11 meter working fine. May I also add that it was working fine in the past when it was installed until few months ago.

    1. Thank you for additional information. I suggest, you let the power company check your meter installation. My guess is, your meter has lost the proper earthing. Depending on the humidity, you have a leakage current in neutral.

  3. My prepaid meter on relay, but since I forward my complain to my company. They gives me temper code more then two times but it doesn’t work please help me.

    1. Only your power company can help you. It’s actually strange, that they give you a clear tamper token without sending someone to check for the reason.

  4. My Cl710k11 uiu keeps reading into negative units even when I don’t have power supply in my home anymore. What could be the reason for this please.

    1. If the meter relay has disconnected, it’s technically impossible that the meter still records consumption. If the relay is still on, you have either still a consumer running, someone else found a way to use your power supply, or you have an earthing fault. Ask your power company to check. They have the tools.

  5. My meter failed to stop after exhausting my credit but continued supplying energy in negative kWh. Can this negative kWh be used to back-bill me? Can the meter be classified as faulty for not being able to cut-off in the first instance?

    1. Thanks for your comment. Power companies can give you allowance for overdraft. Sometimes it’s also named emergence credit. It means the meter is running in negative credit up to a predefined value. Typically, it’s between 20 and 50 units. After that, the meter will disconnect. When you top up the meter, the negative units will be automatically deducted. Example, you have minus 18 units, and you top up 20 units, then your credit will be 2 units.

    1. Thanks for your kind comment. I’ve updated the solution in the article. Take a look again, please.

  6. My clou prepaid meter is not switching on power even after entering the tampered code. Pls help

    1. There are several possibilities:
      a) You need to enter 00 for closing the relay. Some meter types have this additional safety protection to avoid that the meter is switching on unexpected.
      b) The meter is still in tamper mode, because the reason for the tamper is not resolved.
      c) The tamper token has already been used before.

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