2 fixed modbus map – Honeywell HC900 User Manual
Page 26
18
HC900 Hybrid Controller Communications User Guide
Revision 10
12/07
4.2 Fixed Modbus Map
Table 4-2 and Table 4-3 list the the maximum number of Object Addresses and maximum number of registers
allowed per request. Also shown are differences between firmware versions 2.3 and 2.4.
Note 1: In versions 4.0 and higher these maximums apply to fixed map but not to the custom map.
Note 2: In versions 4.0 and higher function code 03 is not available for analog inputs.
Table 4-2 Maximum Number of Objects (fixed map only)
Note: objects marked with * have multiple parameters and therefore occupy multiple registers. For
example, a PID loop has over 40 parameters that can be accessed.
Max. No. of Objects
Object Name
C30
C50/C70/C70R
Function Code
Analog Inputs
96/12 slots v2.3
192/12 slots v2.4
640 v2.3
1280 v2.4
3: can only access first 8
slots of rack 1. Not available
in version 4.0 or higher.
4: can access all slots and
racks
Discrete Input
192/12 slots v2.3
384/12 slots v2.4
1280 v2.3
2560 v2.4
2
Discrete Output/Coil
192/12 slots v2.3
384/12 slots v2.4
1280 v2.3
2560 v2.4
1: read
5: force
Loop* 8
32
3
Variable Value
600
600
3
Set Point Programmer Value*
8
8
3
Segments per Set Point
Programmer*
50 50 3
Signal tags
2000
2000 (C50)
5000 (C70/C70R)
3
Scheduler Value*
2
2
3
Segments per Schedule*
50
50
3
Sequencer* 4
4
3
Stage* 8
8
3
Ramp* 8
8
3
Hand-Off-Auto* 16 16 3
Alternator* 6
6
3
Device Control*
16
16
3
User Defined Registers
1024
1024
3