How to make chaco plots use predefined colormap scale?

Question

I have a set of data that represents thermocouple values at multiple points over time. Using Chaco I have managed to plot a heatmap of the thermocouple locations, with a slider that lets me pick the time step I want displayed. The purpose of this is to compare how the dataset changes over time.

The problem I am having is that the colormap scale changes based on the max and min values shown on screen, but I would like the colormap scale to stay fixed with a predetermined min and max. Is there an easy way to do this using Chaco and Traits? I have looked through the Chaco documentation, but none of the examples I have found cover this situation.

For simplicity, here is a pared down copy of my code. I have replaced my data with a generated dataset of the same shape, with the same value min and max.

import numpy as np
from enable.api import *
from chaco.shell import *
from traits.api import *
from traitsui.api import *
from chaco.api import *
from chaco.tools.api import *

## Random Data
data11 = np.ones([3,5,100])
print data11.shape
for i in range(3):
    for j in range(5):
        for k in range(100):
            data11[i,j,k] = np.random.random_integers(1100)

class heatplots(HasTraits):
    plot = Instance(Plot)
    time = Range(1,99)

    traits_view = View(Item('time'),
                        Item('plot', editor=ComponentEditor()),
                        width=1000, height=600, resizable=True, title='heatmap')


    def datamaker(self):  ## Setting the data time
        t = self.time

        ## Defining the data picker sources
        self.data = data11[...,...,t]

    def heatplotter(self):  ##Making the Plots
        ## The first heatmap                
        self.plotdata1 = ArrayPlotData(hm1 = self.data)
        plot1 = Plot(self.plotdata1)
        plot1.img_plot("hm1", colormap=hot)
        self.plot = plot1

    #_heatplotter()  
    @on_trait_change('time')
    def _new_time(self):
        self.datamaker()
        self.heatplotter()

    def start(self):        
        self._new_time()
        self.configure_traits()

thing = heatplots()
thing.start()

If some of my formating seems odd or round-about its probably because my complete plot includes a datapicker where I can pick between data sets, and it has 2 heatmaps side-by-side in an HPlotContainer. I have removed that because it is not relevant to my question.

Thank you for your time.