Specification Sheet

ManualsBrandsHoneywell ManualsHeating Supplies4-Line 7800 Series Keyboard Display Module

Table Of Contents

7800 SERIESS7800A2142 4Line LCD Keyboard Display Module

320011007 52

The maximum number of addresses that can be queried is 127 (0x7F) for each query

message.

Table 9 through 12 provide information on the function codes.

NOTE: All Query and Response cells below are 1 byte.

Slave

Address

Function

Code

Starting

Address

High

Starting

Address

Low

Number

of Ad-

dresses

High

Number

of Ad-

dresses

Low

CRC CRC

03 or

00 0A 00 01 A4 08

Table 9. Query Message Format for Function Codes 3 and 4.

Slave

Address

Function

Code

Byte Count Data High Data Low CRC CRC

03 or

02 00 22 38 5D

Table 10. Response Message Format for Function Codes 3 and 4.

Slave

Address

Function

Code

Starting

Address

High

Starting

Address

Low

Preset

Data

High

Preset

Data Low

CRC CRC

01 06 00 7F 00 04 B9 D1

Table 11. Query Message Format for Function Code 6.

Slave

Address

Function

Code

Starting

Address

High

Starting

Address

Low

Preset

DataHigh

Preset

Data Low

CRC CRC

01 06 00 7F 00 04 B9 D1

Table 12. Response Message Format for Function Code 6

(There is no response if the query was broadcast.)

Slave Address Function Code CRC CRC

03 11 C1 4C

Table 13. Query Message Format for Function Code 17.

Slave Address

Function Code

+ 80h

Exception Code CRC CRC

Table 14. Exception Response Message Format.

Exception Code Deﬁnition Description

01 Illegal Function

An illegal function as requested. Only 3, 4, 6 and 17 are

supported.

Illegal Data Ad-

dress

Too many bytes requested, address is out of range, reg-

ister is read only, or the number of address requested is

past the last register.

03 Illegal Data Value

The “Preset Data” from function code 6 is invalid/out of

range.

Table 15. Exception Codes.