CleaverBrooks CFC-500 Operation, Service And Parts Manual page 313

Table 13. Pump status codes
(application build 1600 or higher)
Status Description
92 Forced On from manual pump control
93 Forced On due to Outlet high limit is
active
94 Forced On from burner demand
95 Forced On due to Lead Lag slave has
demand
96 Forced Off from local DHW priority
service
97 Forced Off from Lead Lag DHW priority
service
98
Forced Off from Central Heat anti-
condensation
99 Forced Off from DHW anti-condensation
100 Forced Off due to DHW high limit is
active
101 Forced Off from EnviraCOM DHW priority
service
102 On due to local CH frost protection is
active
103 On due to Lead Lag CH frost protection is
active
104 On due to local DHW frost protection is
active
105
On due to Lead Lag DHW frost protection
is active
106 On from local Central Heat demand
107 On from Lead Lag Central Heat demand
108 On from local DHW demand
109 On from Lead Lag DHW demand
110 On from local Mix demand
111 On from Lead Lag Mix demand
112 On from local Central Heat service
113 On from Lead Lag Central Heat service
114 On from local DHW service
115 On from Lead Lag DHW service
116 On from local Mix service
117 On from Lead Lag Mix service
118 On from Lead Lag auxiliary pump X
119 On from Lead Lag auxiliary pump Y
120 On from Lead Lag auxiliary pump Z
121 On, but inhibited by pump start delay
122 On from pump override
123 Off, not needed
124 On from burner demand
125 On from exercise
Some holding registers contain variable length data, e.g.,
register 186 (OS number), that bend the normal Modbus
access for holding registers. Only a single register address is
Note
assigned to these parameters even though they may contain
more than two bytes (16-bits) of data. These registers MUST
be accessed ONLY individually so that no confusion will exist
about parameter boundaries*.
Register Writes
Data registers may require an access-level password before
they can be changed (written) by the Modbus master. For data
registers requiring access security, a password matching the
one contained in the Falcon must be provided before the
Falcon can allow the data to be changed. A valid password
login remains in effect for 10 minutes before another login is
required (Falcon timeout for password login). See User
Interface Data Attribute Table section for more information
regarding how access security is determined.
Two Modbus registers are defined to manage the register data
access login:
• (0x00B1) Password
• (0x0013) Register Access Status
The Modbus master writes a password into the Password
register to request write access privileges to the data registers.
Even though this register is a holding register and therefore
should normally only accept a 16-bit value, it accepts
alphanumeric text up to 20 characters. Owing to this text-
length limitation, change to this register must be written
individually and not as part of a group register write.
Results of the login are reported by the Falcon Modbus in the
Register Access Status register. If the Modbus master writes
the correct installer password, the status register indicates this
result and all data with installer access level and below can be
changed. If the Modbus master writes the correct OEM
password, the status register indicates this result and all data
with OEM access level and below can be changed.
03 (0x03) Read Holding Registers
This function is used to read one or more consecutive data
registers in the Falcon Modbus. The register address of the
first register (see Modbus register map in Figure 1) in the
range is included in the request along with the number of
registers to read. The Falcon Modbus returns a response with
the starting register address, the number of bytes returned,
followed by the register data contents in register address order
(lowest register address first, etc.).
Normally, the number of bytes returned is 2 times the number
of registers requested since each register usually contains a
16-bit value. An exception to this rule is that registers
representing variable length text data return the length of the
text data which can exceed 2 bytes.
06 (0x06) Write Single Register
This function is used to write data to a single register in the
Falcon. The Falcon register address and 16-bit data value
to write into the register are sent to the Falcon, and the
Falcon returns an acknowledgement.
*The standard Modbus protocol does not support the concept of
variable length data. The Falcon Modbus interface varies from the
protocol in that it supports a single register definition for text data.
These special registers must be accessed exclusively by
themselves in order for them to be supported.
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CB FALCON MODBUS COMMUNICATION