Lenze MCH Series Drives Modbus Communications - Manual (Page 11)

7 RG-MHMOD
Drive Setup & Operation
• Setting the control parameter to “NORMAL” or “NORM NO HAND” gives the user read/write access to
the Program Parameters but prevents them from writing to any of the control registers.
• Setting the control parameter to “SERIAL SPEED” or “S SPD / NO HAND” maintains the user’s read/
write access to the Program parameters but also gives the user write access to all control registers
except for SERIAL START. In AUTO mode, the SERIAL SELECT, SERIAL SPEED and SERIAL PID control
registers can be used to control the drive speed or PID setpoint. Writing a 512 (200h) to the Drive
Control register sets the SERIAL SELECT flag thus commanding the drive to follow the SERIAL SPEED
or SERIAL PID command register. Writing a 256 (100h) to the Drive Control register clears the SERIAL
SELECT flag returning speed control to the previously selected source. The user can still write values
to the SERIAL SPEED and SERIAL PID registers but they will not be used until the SERIAL SELECT flag
is set again.
• Setting the control parameter to “SERIAL AUTO” or “S AUTO / NO HND” provides the user with all of the
functionality of the “SERIAL SPEED” and “S SPD / NO HAND” settings with the addition of the SERIAL
START command. Under these settings, when the drive is in AUTO mode, it can only be started via the
serial link.
All control options are subject to the Parameter and Control Locking/Unlocking procedures.
4.4 Unlocking & Locking Controls
Registers #48 and #1 are used in Unlocking and Locking Controls.
• A write to Register #48 (Unlock Controls) with a value of 0 will unlock controls. This enables the writing
of Register #1 – the Drive Control Register.
• If Register #48 (Unlock Controls) is written with a value that is the Drive’s Programming Password, then
in addition to Register #1(Drive Control), writing to all other writeable registers is enabled (e.g.: register
#52 -- Preset Speed #1). The factory default password for MH series drives is 19.
• Once Register #48 (Unlock Controls) has been written, Controls are unlocked until the Lock Security
flag (Bit 1 of Register#1) has been set or until a Watchdog Timeout occurs.
• Writing to Register #1 (Drive Control) with bit 1 set will Lock both Controls and Parameters (prevents
writing to any register).
• The serial drive control can only be unlocked when the drive is not in programming mode.
• When LOCK is asserted, the drive drops out of SERIAL control and reverts back to the previous source
of control.
• Even though drive might be locked, and thus parameters and control cannot be written, parameters
and status can always be read. Refer to section 4.7, Monitoring Only Operation .