EATON MTL838C Temperature Multiplexer System Instructions
- June 12, 2024
- EATON
Table of Contents
CROUSE-HINDS SERIES
Technical support note
MTL intrinsic safety solutions
Supporting the LLMUX with the MTL838C
MTL838C Temperature Multiplexer System
Eaton has designed the MTL838C according to Honeywell LLMUX spec. To support Honeywell LLMUX with the existing installation, we propose the below workaround for easy configuration of the MTL838C.
-
The out-of-box default for the MTL838C will be Modbus mode. The following would need to be done for each MTL838C using the PC Software:
a. The HW user will need to switch the MTL838C to LLMUX mode (a single dropdown box).
b. They will then need to configure the number of 831Cs connected to the 838C.
By default both are enabled.
c. Finally select the input type for each MTL831 connected to the MTL838C.
mV/THC is the default but RTD may be selected instead. -
The MTL838C will interpret the Configuration codes from the HW system exactly as documented previously for the MTL838B – EXCEPT that all RTDs will be assumed to be 3-wire type.
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If the HW user wants to use a 2-wire or 4-wire RTD, they will have to use the PC software to configure the channels. The PC Software is the only way to change the number of wires for RTD types. This is selectable on a channel by channel basis.
The PC configuration options will be:
| Index | Description | HW Codes |
|---|---|---|
| 0 | Not Configured (default) | De-configure command |
| 1 | Voltage (mV) | 0x0C, 0x7E, 0x7F |
| 2 | 2W RTD Ω | 0x08, 0x09, 0x0A, 0x0B |
| 3 | 3W RTD Ω | 0x08, 0x09, 0x0A, 0x0B |
| 4 | 4W RTD Ω | 0x08, 0x09, 0x0A, 0x0B |
| 5 | TC, B, mV, CJC | 0x04 |
| 6 | TC, E, mV, CJC | 0x02 |
| 7 | TC, J, mV, CJC | 0x00 |
| 8 | TC, K, mV, CJC | 0x01 |
| 9 | TC, R, mV, CJC | 0x06 |
| 10 | TC, S, mV, CJC | 0x05 |
| 11 | TC, T, mV, CJC | 0x03 |
NOTES
- The Not Configured mode would be implemented as mV in the 831s as they always have to be doing something.
- The HW system does not ask the LLMUX to return the channel configuration code so multiple codes (that make the same measurement) can be represented by one input type.
Eaton Electric Limited,
Great Marlings, Butterfield, Luton
Beds, LU2 8DL, UK.
Tel: + 44 (0)1582 723633
Fax: + 44 (0)1582 422283
E-mail:mtlenquiry@eaton.com
www.mtl-inst.com
© 2018 Eaton
All Rights Reserved
Publication No. TSN838C LLMUX Rev1 020718
July 2018
Documents / Resources
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EATON MTL838C Temperature Multiplexer
System
[pdf] Instructions
MTL838C, MTL831, MTL838C Temperature Multiplexer System, MTL838C, Temperature
Multiplexer System, Multiplexer System
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