CAL Controls 3300 Communications Manual page 4

1.1 Internal data formats
The instrument stores data in a variety of ways to allow a full range of values to be held in the minimum
space possible. Most are represented by a multiple of the displayed value - this is given as a scale
factor in the table below: for instance, temperatures are stored in 10ths of a degree, so a displayed
value of 123.4 degrees is stored as 1234 - this is shown in the tables as temp * 10. Some time values
are stored in 40ms units so a time of 1 second would be stored as 25. A few parameters - mainly the
times - have different scale factors and offsets depending on their current value - these are detailed
individually.
Parameters are incremented/decremented by fixed step sizes depending on their current value within
limits which may change depending on the current value of other parameters. Many parameters
increment and decrement in the same manner - this is referred to in the tables as normal inc/dec - in
these cases parameters move in 0.1 steps between —9.9 and 9.9, otherwise in steps of 1. Note that
when incrementing or decrementing, the internal storage format must be taken into account and also
whether the display is in hi-res mode - values sent to the instrument must match the current mode.
Note also that in the 9500 instrument parameters marked with [LIN] are stored in degrees*10 when the
selected input is a thermocouple or RTD and units of 1 when the selected input is linear. Also note that
while linear input is selected the display of values on the instrument is effected by the setting in DECP
not Disp.
The instrument provides no error checking on values transmitted to it - the user must ensure that new
values are checked for consistency before uploading.
1.2 Variables not on menu structure
Parameter Size Address
Name (hex)
SP1 2 007F
Setpoint 1 0125
safety check
Temperature 2 001C
security byte 1 0300
Ramp Byte 1 0305
Display Byte 1 0306
Display State 2 0205
Model 2 04FC
(Type of inst
and output
configuration)
The Ramp and Display bytes have been kept together so that a single word read at address 0x0205
can be used to obtain full information about the state of the instrument display.
COMMERCIAL IN CONFIDENCE
R/W ModBus Internal Storage, Step rate in
Function Internal units
read/write
RW 3/6 Degrees * 10 [LIN]
step 1 from LoSc to HiSc
RW 3/6
R 3/6 Degrees * 10 [LIN]
W 6 no scaling
R 3 no scaling
R 3 no scaling
R 3 no scaling
R 3 0X01 33/9300 RLY / SSD
0X02 33/9300 SSD / SSD
0X03 33/9300 RLY / RLY
0X07 9400 RLY / SSD
0X08 9400 SSD / SSD
0X09 9400 RLY / RLY
0x10 9500 SSD / RLY / RLY
0x11 9500 SSD / SSD / RLY
0x12 9500 RLY / RLY / RLY
0x13 9500 ANLG / RLY / RLY
0x14 9500 ANLG / SSD / RLY
Page 3
Comments
The setpoint required. See 1.2.1
below regarding initialising a new
instrument
see note 1.2.1 below for correct
usage of this byte
stored as 10ths of deg C
see 2.3 for security messages
see 1.2.2 below for bit meanings
see 1.2.3 below for interpretation
a word read enables Ramp byte
and Display Byte to be read with a
single message
Type of instrument and output
configuration are determined by
the hardware, but can be read
from the address 04FC